fairbairn



2 Sheets- Sheet 1.,

C. PAIRBAIRN Su MWELLS.

APPARATUS PoR PoRGNG- som-Ws.

atented Aug. 7, 1894.

-2 Sheets-Sheet 2. C. FAIRBAIRN 81: M. WELLS.

APPARATUS FOR PORGING SGREWS.

No. 524,199. Patented Aug. 7,I 1894.

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Witheases,

Pneus co.. FHOTQUTHQ.. WASHING-mn u c 'UNITED STATES PATENT Genion.

CHARLES FAIRBAIRN AND MATTHEV IVELLS, OF MANCHESTER; ENGLAND.

APPARATUS FOR FORGING SCREWS.

SPECIFICATION forming partof Letters Patent No. 524,199, dated August 7,1894. Application filed October 28.`1892. Serial No.450,19'7. (Nomodel.) Patented in Englandd'annary 25, 1892. No. 1,421.

.To all whom it may concern:

Be it known that we, CHARLES FAIRBAIRN and MATTHEW WELLS, subjects ofthe Queen of Great Britain and Ireland, residing at Man-- chester, inthe county of Lancaster, England, have invented certain new and `useful1mprovementsx in Apparatus for Forging Screws, of which the followingisa specification.

This invention relates to the construction and arrangement in machinesfor forging screws, of the rollers or disks between which entinventionto remove.

the screws are forged, and has been patented in Great Britain, No.1,421, January 25, i892. In such machines as at present constructed thescrews are forged between the faces of two opposed disks, the existingconstruction and arrangement of these rollers are open to objectionswhichit is the object of the presthe screws are forged betweentheopposed faces of two disks or rollers, the grooves by means of whichthe threads of the screw are formed, are annular and concentric with theaxis of rotation of the disk. The disks are arranged eccentrically withrespect to each other and the longitudinal motion of the screw isproduced by the pressure at angles exerted by the disks in rotation. Inorder to make the annular grooves of the opposed disks cross each otherat a sufficient angle, their respective axes of rotation have to beseparated to such a distance that the blank or screw shall move throughthe distance of the pitch for each of its rotations. Consequently enoughwork cannot be put upon the screw l to Iinish it properly, while at thesame time, the threads are part] y raised and partly sunk, and theraised half or portion of the thread has a larger diameter than theblank or unscrewed part.

According to our present improvements when the grooves are formed on thefaces of two opposed disks, instead of making them annular, we form themin spirals over a comparatively narrow band near the edge of eachl disk.The two disks are arranged with their working faces parallel or inclinedand opposed, and with their axes eccentric,

f We will more particularly describel our said invention with referenceto the accom panying drawings, in which- Flgure 1 is a longitudinalsection, and Fig.

For example, when 2 a plan ot' a machine in which the screws are forgedbetween two opposed disks. Fig. 3 is an end elevation taken to the leftof Figs. l and 2, and Fig.4is an end'view, partly in section, showingthetreadle motion. Fig. 5 is a detail showing the gearing required torotate the disk to the left in an opposite di rection to that of thedisk to the right. Fig. 6 is a plan of one of the disks showing thespiral grooves formed on the annular band on the face of the disk. Bothof the disks are formed alike. Fig. 7 is a section through the disk.Fig. 8 is a plan showing the eccentric ,arrangement of the two opposeddisks. Fig.

9 is a section taken along'the line -y Fig. 8. The disks illustrated byFigs. 6 to 9, inclusive, are drawn to an enlarged scale. Fig. 10 is adiagram illustrating the manner of laying out the grooves. v

We have illustrated our Aimprovements as applied to existing machines inwhich the l rollers'are arranged in vertical planes, Ybut thereis noreason, other than that of` convenience, why they should not be arrangedhorizontally and we may so arrange them without departing fromourpresent invention.

In the machine illustrated by Figs. l to 4 inclusive, the t-woopposedrollers or disks A. A. are rotated in opposite directions from the shaftB, which is driven by the fast and -loose pulleys C. On lthe hollowspindles D D. are fixed the wheels E E. which gear, E with thepinion Fon the shaft B, and "E" with the pinion F. on the stud G, the pinion F.also gearing with the pinion F2. on shaft B. In consequence 'of theintermediate pinion F', the shaft wheel E., and consequently its shaftalso, is driven in the opposite direction to that of E, andthe disksrotate oppositely.l The hollow spindle D on which one of the disks ismounted is capable ot' longitudinal movement so as to enable it to bebrought nearer to or be removed farther from the other disk. Thisv isfor the purpose of enabling the heated blanks to be inserted andwithdrawn at the commencement and end of each operation and isaccomplished by the treadle H, which acts through the intermedi- -`aryof the links and arms I I. upon the clutch .I fixed upon the pushspindle K.. This acts in one direction only, the return of the IOO diskbeing effected by means ofthe spring y L. The amount of eccentricity ofthe disk is regulated by means of the adjusting screws M M. and theswing arm G. of the gearing shown in Fig. 5, keeps the pinion fully ingear With the wheel'E., notwithstanding the eccentricity.

lThe grooves on the annular band may be set out as illustrated by thediagram Fig. lO. From the center o. draw as many equidistant radiallines 1. 2. 3. n, as there may be dtsired spirals in the annular band.In the example, there are supposed to be eight. With any convenientradius, which in the majority of cases may be taken from twelve tofifteen vcentimeters, set out the circle a. At a distance equal to aboutsix or seven tenths of the diameter of the blank to be used in producingthe screws, set out the inner vand outer circles b. c. which will formthe boundaries of the annular band. From the point of intersection ofcircle b and radins 2. at an angle of forty-five degrees from theradius, set out the line b d, terminating on the circle c. Bisect b. d,and draw therefrom the line c f. From the center o, draw the line 0 g,parallel with b. d, and cutting the line ef. Through the point ofintersection t' of The lines e f, and 0 g from the center 0, describethe path of centers p, on which the centers of all the spiral curveswill be found. The radius of curvature of the spirals is b i. The line bd, may be at a greater or less angle, according as a flat or roundspiral is desired.

The amount of eccentricity between the centers of the disk must beseparately determined in each case, and will vary with the amount ofwork to be done in making the screw. The greater the eccentricity, themore rapidly will the screw be forged, but this means also that thewhole work of forging must be done in less time. For average cases theamount of eccentricity may be taken as one half to three fourths of theradius of the path of centers p.

The edges of the annular band should be beveled down as shown in Fig. 7.The beveledL edges are a necessity to the y,disks in practical work toenable the blanks to enter and vto be seized between the disks. If theedges were not beveled, the commencement of the work on the heatedblanks would involve a very sudden and heavy shock, which the bevelingof the edges softens and renders harmless.

The insertion of the heated blank, and the release of the finished screware effected by causing the disk A to approach the disk A. afterinserting the blank, by means of the treadle H. As soon as the screw hasbeen forged, the treadle is released and the spring L then forces thedisk back, when the finished screw may be removed. It is preferred torotate the disks in such a direction that the blank is fully inserted,and is forced out by the action of the disks in forming the screw, inthe direction shown by the arrow Fig. 8, Where the screw is representedas being partly formed. The extent of the motion of the disk may beadjusted for different diameters of screws by means of the usual stop,or by IiX- ing the clutch J on the push spindle nearer to or fartherfrom the contiguous bracket which then forms the stop.

A plane or roughened feeding rim N may be formed within or outside andconcentric with, the annular band, according to the direction ofrotation. Thus, if the blank moves in the direction shown by Fig. S, thefeeding rim is constructed inside, if in .the opposite direction,outside, the annular band.

The disks may be secured by set screws passing through the anges O O.formed upon the ends of the hollow shafts D D., and their concentricposition thereon may be secured by forming circular projections thereonwhich fit within the annular disks.

Having now particularly described and ascertained the nature of our saidinvention and in what manner the same is to be performed, we declarethat what we claim isl. In a screw forging machine, two opposed rollerseach having on its face a narrow raised, annular band, containing spiralscrew forining grooves, and a flat feeding band concentric with andadjacent to said raised groove band, substantially as described.

2. In a screw forging machine, a roller having on its face a narrowraised annular band, containing spiral screw forming grooves and havingbeveled edges, and a dat feeding band concentric with said raised band,substantially as described.

In testimony that we claim the foregoing as our invention we have signedour names, in

presence of two Witnesses, this 6th day of Au- '1405 gust, 1892.

CHARLES FAIRBAIRN. MATTHEW WELLS.

Witnesses:v Y

WM. E. HEYs,

GEORGE W. Rows.

